The Application of Chemical Polishing in TEM Sample Preparation of Zirconium Alloys.

Fusheng Li,Huan Tong,Shilei Li,Hainan Xu,Yanli Wang

doi:10.3390/ma13051036

Abstract

Hydride artefacts are commonly induced by the TEM sample preparation process in Zirconium alloys as hydrogen-sensitive metals, including electron polishing and focused ion beam (FIB) technology. In the research, we present the application of chemical polishing with a solution of 10HF:45HNO3:45H2O to prepare the disk samples for TEM observation in zirconium alloys. The thinning efficiency of chemical polishing is 25 μm per minute. XRD patterns indicate that the chemical polishing actually eliminates the macro- and micro-stress induced by mechanical grinding. TEM observation demonstrates that chemical polishing reduces the amount of hydride artefacts, especially hydrides with large size. It is proposed that induced stress provides driving force for hydride artefact formation. Compared with traditional mechanical grinding, the advantages of chemical polishing are high efficiency, free of induced stress, less induced hydride artefacts and bend contours.

Highlights

Zirconium alloys have been widely used as fuel cladding materials in light water and pressurized water reactors due to their low thermal neutron cross section, good corrosion resistance and mechanical properties [1,2,3]
We present the application of chemical polishing with a solution of 10HF:45HNO3 :45H2 O
We present the application of chemical polishing3 :45H

Summary

Introduction

Zirconium alloys have been widely used as fuel cladding materials in light water and pressurized water reactors due to their low thermal neutron cross section, good corrosion resistance and mechanical properties [1,2,3]. These zirconium claddings experience microstructure evolution and mechanical property changes under fast neutron irradiation and corrosion reaction [4]. The induced hydride artefacts are the major challenge during TEM sample preparation, including traditional twin-jet electron polishing and focused ion beam (FIB) milling. Traditional twin-jet electron polishing to prepare TEM sample of Zirconium alloys requires more attention to reduce the hydride artefacts

Methods

Discussion

Conclusion